Gravel and pea shingle have two primary purposes on a flat roof.
Why do you put gravel on flat roofs.
To weigh down or secure the roofing material as is the case with single ply flat roofs.
Gravel is used on flat roofs for two reasons.
As ballast the gravel will help anchor the material underneath and lower the risk of it being blown off in high winds.
Most flat roofs traditionally have tar applied over the roof decking to make it watertight.
So all you need to be able to say to your roof contractor is you want an epdm rubber roof.
Walking on the tar would hurt the tar s seal fast.
Contractors and builders use gravel on flat roofing for two primary reasons.
Why do you put gravel on a flat roof.
Walked on gravel tends not to hurt the seal of the tar underneath.
They provide a loading coat and they afford uv protection.
The gravel covers a tar roof.
Also the gravel acts as a wick to pull up any water left on the roof after scuppers or gutters lead excess water away.
A built up roof bur.
The first is to protect the underlying layer of roofing materials on built up roofs burs and the second is to secure or weigh down the roofing material as is the case with single ply flat roofs.
Flat roofs usually come with a 10 to 20 year warranty but can last 25 years if you build the roofs right and maintain them using commonsense rules.
First of all it weighs down the covering surface of the roof and secondly it protects the roof from sun damage.
Built up roof bur the traditional hot tar and gravel roof is built from three or more plies of waterproof material alternated with hot tar and ballasted by a layer of smooth river stone.
Gravel to protect built up roofs.
To protect the underlying layer of roofing materials as is the case with built up roofs burs.
These roofs are installed as thin sheet materials 0 030 30 mils to 0 060 inches 60 mils thick and are applied to the roof in a single layer.
Gravel collects along gravel stops drip edges causing more heat and moisture to be directed against the roof surface causing damage over time.